The University of Pittsburgh was one of the founding institutions of the Primary Breast Cancer Therapy Group (NSABP) in 1958 and has continued uninterrupted as a major participant and contributor to the various group protocols. Patients (450) have been entered into protocols evaluating the relative efficacy of radical and total mastectomy with and without postoperative radiation, segmental mastectomy and a variety of protocols employing chemotherapy in various combinations alone or with the antiestrogen tamoxifen or C. parvum. Since all patients had Stage I or II breast cancer and received prolonged adjuvant therapy, protracted intensive follow-up continues to be involved. For example, in Protocol No. B-04 into which 200 patients were entered 70% of patients are still being followed despite the fact that the average time on study is almost 6 years. In addition to entering patients into protocols and providing the NSABP Headquarters with high quality data, this institution has been instrumental in providing patients and material for carrying out biological and ancillary studies generated by protocol findings. For example, a Phase I study was carried out entirely at this institution to obtain additional information relative to dosages of CP in humans and more exact information on the toxicities which occur following administration of this agent. In another investigation utilizing serum samples from patients in this institution it was found that there was a lack of association of disease-free survival following adjuvant chemotherapy with depression of ovarian function. More recently, we have carried out a pilot study at this institution to evaluate the mutagenic effects of cytostatic drugs on human lymphocytes. The present application seeks funding (a) to continue to follow patients who have been entered into protocols which have been terminated, (b) to permit patient accrual in ongoing protocols, (c) to participate in the design of new protocols and the accrual of patients in new protocols, and (d) to collect appropriate biological material and information relevant to such protocols. Finally, this proposal provides the single most important mechanism for promoting the multidisciplinary treatment of cancer via clinical trials in this environment.